namespaces

[Paolino]

Steven D'Aprano wrote:

> def translate(text):
>     import string
>     all=string.maketrans('','')
>     badcars=all.translate(all,string.letters+string.digits)
>     table=string.maketrans(badcars,'_'*len(badcars))
>     return text.translate(table)
> 
> No pollution.

And no efficience.Recalculating all,badcars and table was not an 
acceptable solution ,sorry if I didn't state this point :(

> Then after you are finished with the bindings, delete them:
> 
> import string
> all=string.maketrans('','')
> badcars=all.translate(all,string.letters+string.digits)
> table=string.maketrans(badcars,'_'*len(badcars))
> def translate(text):
>     return text.translate(table)
> # clean up the temporary variables so as to prevent namespace pollution
> del string; del all; del badcars; del table

Well,a solution but not a programming pattern for an elegant language ?
More this is also loosing informations.

Probably I've not been clear with the word pollution and the example is 
poor.
I didn't mean 'binding to unuseful informations' but 'bindings  in a non 
-structured organization'

I restate the problem.Python is in some ways unable to project the 
module structure inside the module.Or ... namespace pattern instances 
seems  not deriving from a common pattern.

Finally, (before I get polemic which is not my aim) I start thinking 
classes (namespaces defined via 'class' keyword) are a specialization of 
generic namespaces in which there-defined methods get a special way of 
being called and __call__ method is a way of cloning access to them.
(Thin ice....)

Don't really know if modules can be defined as specialization  of 
generic namespaces and be placed somewhere next to classes.

Even worse I get with methods and function namespaces.

Rob Williscroft wrote:

 > After 3 or 4 iterations I refactored you code to this:
 >
 > def translate( text )
 >     import string
 >     all=string.maketrans('','')
 >     badcars=all.translate(all,string.letters+string.digits)
 >     TABLE = string.maketrans(badcars,'_'*len(badcars))
 >
 >     global translate
 >     def translate( text ):
 >         return text.translate(TABLE)
 >
 >     return translate( text )

There is a way to access 'all' and 'badcars'  here?

In my trial translate.all and translate.badcars can be accessed easily 
and maybe coherently.

Thanks a lot, and don't tell me 'the dictator has marked the trail' ;)

	

	
		
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